This paper exploits semantics to apply context in run-time adaptation, particularly for services in a user-centered smart environment. Context-sensitive services are usually focused on their own information without interoperation pretensions. It is necessary to enable common context models and systems in order to make context-aware applications interoperable. Moreover, context management systems need to implement mechanisms to support the dynamic behavior of the users and their surroundings, including techniques to adapt the model to their future needs, to maintain the context information at run-time and to be interoperable with external context models. By adapting web semantic technologies we can enable smarter and more proactive operation of context management systems. Copyright © 2010 John Wiley & Sons, Ltd.